Rule Change: Add suggestions to no-constant-binary-expression about eslint

[mdjermanovic]

function a():boolean{
  ...
}
if(!a){
// !a always return false, and didn't report an error 
  ...
}

This case is included in #13776 proposal, so I'm closing this issue as a duplicate.

[bradzacher]

You could use scope analysis to attempt to resolve an expression to a static value (I believe there's already a util function you guys use for this purpose!) which would let you provide extra help messages for some cases.

[Tanujkanti4441]

Hey @littlemoji, thanks for the issue, i am a bit confuse, your title says 'to add suggestions' but from the code example you have given seems like the issue is about to enable the rule to check the types also, can you clear this.

[aladdin-add]

it's confusing: "suggestions" is a term used in eslint: https://eslint.org/docs/latest/extend/custom-rules#providing-suggestions. 😄

If you're proposing to report an error in the code in the example, this is not possible in eslint because eslint doesn't have type information. But it's possible in ts-eslint. /cc @bradzacher

[bradzacher]

If you want a rule which warns against constant/unnecessary conditions - we have that - https://typescript-eslint.io/rules/no-unnecessary-condition/